I went to Food Pyramid and just picked up some of their $4 bunches in fall colors. These are rust asiatic lilies, yellow mums, ivory spray roses and green hypericum berries.
I had a square vase at home (my favorites) and started with the asiatic lilies. I kind of arranged them on three of the corners to make it kind of take up most of the vase as a base.
Next, I added the clumps of spray roses.